Cryptococcal meningoencephalitis in a dog presenting with ocular clinical signs treated with fluconazole and amphotericin B in the UK

Abstract A 4‐year‐old, male neutered, labrador retriever was referred for evaluation of unilateral blindness and blepharospasm. The dog had no travel history. The left eye had a bullous retinal detachment, multiple intra‐retinal haemorrhages, and moderate aqueous flare. General physical examination, blood and serological testing, urinalysis, and abdominal ultrasound were unremarkable. Thoracic radiographs displayed a mild broncho‐interstitial pattern. Treatment with topical and systemic corticosteroids was commenced, and clinical improvement was seen. Three weeks later, the dog developed Horner syndrome. Swollen optic nerve heads and multiple chorioretinal lesions were observed on indirect ophthalmoscopy. Magnetic resonance imaging revealed bilateral optic neuritis. Cerebrospinal fluid cytology revealed encapsulated yeast‐like structures, and a panfungal polymerase chain reaction identified Cryptococcus neoformans , further supported by a positive cryptococcal antigen titre. Treatment with fluconazole and dexamethasone was commenced, but the cryptococcal antigen titre increased. Amphotericin B was added, and the clinical signs resolved. The dog remains in clinical remission 2 years following diagnosis.